Douglas Carswell has never, as far as I know, been a Tory – that’s to say, a believer that authority in Britain originates from its institutions: the Monarchy, Crown in Parliament, the Church of England. For as long as I’ve known him, he has always been not exactly a Whig but certainly a radical. This isn’t to say that he is a republican or has non-Anglican religious beliefs or that he doesn’t revere the House of Commons (far from it), but that he sees authority as flowing from the people rather than from elsewhere. He is in the tradition of Cobden and Bright rather than that of Shaftesbury and Macmillan. To consider his defection in this way may seem abstracted, not to say abstruse. But it is the right way to go about it, because Carswell is, first and foremost, a man to whom ideas matter. The Plan, which he co-wrote with Daniel Hannan, suggested so. That he is prepared to resign his seat and fight a by-election confirms it.

For what it’s worth, my sympathies are with the Tory tradition, and I thus have an uncomfortable feeling that, were I somehow to find myself in some Sealed Knot re-enactment of the English Civil War, I would find myself at pinioned to the ground by a grinning Carswell at a pike’s-end. To say that we are not natural soul-mates is thus an understatement. I none the less like him, admire him and am amused by him, in more or less equal measure. This is partly a product of déformation professionnelle: journalists like politicians who are compelling, unusual, fun, interesting, outspoken and are reluctant to be guided by the Whips. It may also be a sign of something that reaches deeper – that his days of fellow-travelling with Conservatives are not yet over.

True, Carswell is not only not a Tory, but is also, of today, no longer a Conservative with a capital C. But this doesn’t mean that he isn’t a conservative with a small one. That this is so should be the Party’s guide in how to treat him now, as well as other members who may defect. Very simply, Carswell may be more of a Gladstone rather than a Disraeli, but he is also very much a Thatcher – that’s to say, a follower of the Party leader who brought nineteenth century liberalism into uneasy alliance with twentieth century conservatism, and won three elections off the back of it. And UKIP has its Thatcherite wing. Carswell now finds himself more or less at the head of it. For the time being, he has a seat in Commons. He may hold it in the by-election he has promised. Even if he does not, he is likely to remain a player within a party that Nigel Farage will not lead forever.

Yes, I believe, like Mark Wallace, that his EU-related reasons for leaving the Party don’t add up. (He understands well that there’s a place for Outers within it: indeed, they now all but constitute a majority among members.) Yes, I think that UKIP’s opportunist bandwagon is unworthy of him – and suspect that he may swiftly find this out. And, yes, I hope he loses the by-election.

But this is not to say that he has acted dishonourably or even mistakenly. Rather, he has come to believe that there is no place for his iconoclasm in a party led by David Cameron. That this is so is not entirely his fault. For example, Downing Street could have taken up his vigorous ideas on party revival – and Carswell with them, perhaps utilising his brains and energy as a Party Vice-Chairman.

However, might-have-beens are less important, in this case, that what might still be. But whatever happens, the departure of this untameable individualist should be treated not as a trigger for abuse, but as a parting of friends.